City crews began dismantling San Jose's massive homeless encampment known as "The Jungle" Thursday morning.

Thought to be the largest homeless encampment in the United States, the 75-acre camp was home to about 300 people. Most lived in tents, shacks and tree houses amid piles of trash.

The city says the camp must be cleared because of increased violence, wet weather and unsanitary conditions that are polluting nearby Coyote Creek.

"Living conditions that constantly jeopardize [lives of the homeless], put the environment at risk and put the surrounding safety of the neighborhoods in jeopardy is not a situation we can tolerate as a city," said Ray Bramson, San Jose's homeless encampment project manager.

Residents were given notice Monday that they had to leave or face arrest for trespassing. This morning, about 60 residents remained at the camp, dragging their belongings through ankle-deep mud as they made their exit. Some had friends pick them up in cars or vans, while others left on foot with shopping carts filled to the brim.

Resident Robert Aguirre says the closure is baffling, because for years police and social workers sent people to The Jungle after closing other encampments across the city.

"By shutting this down you’re actually making these people homeless," he said on KQED Forum. "A lot of these people have been here for as much as 20 years. They built homes for themselves. They’re waterproof, they’re weatherproof, they’re just nontraditional homes. Now they’re going to be forced out into the streets."

San Jose has cleared out The Jungle in the past, most recently in May 2012, when 150 people were evicted. Aguirre said that it was only a matter of weeks before residents returned.

This time, the city says, the eviction is final. They've dedicated $4 million to cleaning up the site and providing housing subsidies for residents.

Social workers have spent the past few months finding housing and jobs for residents. Instead of clearing camps as they have in the past, the city is taking a "housing first" approach, Bramson said.

They've placed 144 people in permanent homes and another 55 will be housed soon, Bramson said. Nearby shelters have also set aside designated beds for camp residents.

But some housing advocates say the closure should have been postponed until more alternative housing could have been found, and that the housing subsidies aren't enough.

"What [the city] does, is they fail to provide housing for people, and then they blame the homeless and think they can solve the problem just by moving them around," said housing advocate Sandy Perry.

Nearby companies like Google, Apple, Yahoo, eBay and Facebook have amassed incredible wealth as the tech sector roars back to life following the recession. The growth has driven up home prices in the Bay Area, and many available units are unaffordable for low and middle-class residents.

"To not be able to house our people in the richest place in the world at the richest time in its history shows us that something's completely broken about our city," Perry said.

The Associated Press contributed to this report.